title: Intramolecular cyclization of N-phenyl N'(2-chloroethyl)ureas leads to active N-phenyl-4,5-dihydrooxazol-2-amines alkylating β-tubulin Glu198 and prohibitin Asp40.
abstract: The cyclization of anticancer drugs into active intermediates has been reported mainly for DNA alkylating molecules including nitrosoureas. We previously defined the original cytotoxic mechanism of anticancerous N-phenyl-N'-(2-chloroethyl)ureas (CEUs) that involves their reactivity towards cellular proteins and not against DNA; two CEU subsets have been shown to alkylate β-tubulin and prohibitin leading to inhibition of cell proliferation by G₂/M or G₁/S cell cycle arrest. In this study, we demonstrated that cyclic derivatives of CEUs, N-phenyl-4,5-dihydrooxazol-2-amines (Oxas) are two- to threefold more active than CEUs and share the same cytotoxic properties in B16F0 melanoma cells. Moreover, the CEU original covalent binding by an ester linkage on β-tubulin Glu198 and prohibitin Asp40 was maintained with Oxas. Surprisingly, we observed that Oxas were spontaneously formed from CEUs in the cell culture medium and were also detected within the cells. Our results suggest that the intramolecular cyclization of CEUs leads to active Oxas that should then be considered as the key intermediates for protein alkylation. These results will be useful for the design of new prodrugs for cancer chemotherapy.
authors.affiliation: U990 INSERM, Rue Montalembert, BP 184, 63000 Clermont-Ferrand, France. trzeciakiewicz@gmail.com
authors.forename: Anna
authors.initials: A
authors.lastname: Trzeciakiewicz
authors.forename: Sébastien
authors.initials: S
authors.lastname: Fortin
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Moreau
authors.forename: René
authors.initials: R
authors.lastname: C-Gaudreault
authors.forename: Jacques
authors.initials: J
authors.lastname: Lacroix
authors.forename: Christophe
authors.initials: C
authors.lastname: Chambon
authors.forename: Yves
authors.initials: Y
authors.lastname: Communal
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Chezal
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Miot-Noirault
authors.forename: Bernadette
authors.initials: B
authors.lastname: Bouchon
authors.forename: Françoise
authors.initials: F
authors.lastname: Degoul
mesh_terms: D000477:Alkylating Agents / Q000494:pharmacology*; D000588:Amines / Q000737:chemistry / Q000378:metabolism*; D000818:Animals; D001224:Aspartic Acid / Q000378:metabolism*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002851:Chromatography, High Pressure Liquid; D003500:Cyclization; D015180:Electrophoresis, Gel, Two-Dimensional; D005455:Fluorescent Antibody Technique; D018698:Glutamic Acid / Q000378:metabolism*; D008546:Melanoma, Experimental / Q000473:pathology; D051379:Mice; D000091402:Prohibitins; D012097:Repressor Proteins / Q000737:chemistry / Q000378:metabolism*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014404:Tubulin / Q000737:chemistry / Q000378:metabolism*; D014508:Urea / Q000737:chemistry / Q000378:metabolism*
chemical_list: D000477:Alkylating Agents; D000588:Amines; D000091402:Prohibitins; D012097:Repressor Proteins; D014404:Tubulin; D001224:Aspartic Acid; D018698:Glutamic Acid; D014508:Urea